SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a60f7727495acd145ca15a5b30a79073d0e524b3d31c2cbb1c60cb273cd185' 
  AND token = '6z8JFcsPxKEmpf3I+mJm+OH5cjMZmmwYg4XWJsIWRO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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