SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0feeab7950e84111e4495c200396337c7a086c16932f1e94742c4fb2d541c64' 
  AND token = 'rcq5diyIhqEmkgDDnrCIWSJOnD6kScqogp7ZebIBRxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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