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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1e75b2671a9c6128e3bd66dd409162e372fe79a98d35622eddf7c08b6d97e7' 
  AND token = 'wvPuiY3oDqoU4dIi2dylTqu0OnOQQcYDl/goTDqjPNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}