SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1b5be3f15ea82fa07515fe9dc7b2b8596e67eb6463fb3c650de62f87b1c3a47' 
  AND token = '/jlKsSFNjnOYwH5NZeQkjqhz4/Kt/UMYa7Kx5qNL3Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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