SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ca3fa92e538f14052e3458892e5efea63a6e7609e02d9a59adc9cabccf8f145' 
  AND token = 'cP5JZIZGDKFwkLXaAolh3jzNr7UeVDRNgbl5k7ajp1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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