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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a878f20af1368c0b362f98c98d20a521f442645c3a738990307571f46c45f1c0' 
  AND token = 'L09U6T51w9sY089ec4nC357KRB0bzsIjuHQRJ+ImD+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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