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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4af9c3d9a2969c0bcb1f94181a18e4cefd7aecc0f228f3c8eb11c2cc422e5e4' 
  AND token = 'h5DzNiKki9TDHxTPBmibY/AXSs78hw/Pn+Mkd/DLZDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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