SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11c0943c404b3841f2b17c93058dff4ae02bc77d07b067e6c16c276cb27456ac' 
  AND token = 'U+mmOVp0bHeQCmOUAzv3ixHf/VnrUyjDAEWvMYLBBjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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