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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b5ac7a97e9bb0fb1f588a90fa157e7a9776c67240f9db9acec8cc13a27b8c762' 
  AND token = 'KhiU5zBDsWkaVLqh9EPMDIn7Eq8Ewxy0E+1j7SKkEHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}