SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1913d39f88e867be3e9bbd2d2434f5220b2d2f4537a22013994d0f7594384299' 
  AND token = 'yLlSvggMEPvYKUghqcluBh/oxXPH2BsKXPeBRHvwIo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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