SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '138c6dfa218c50e0b5ea1238071f30feea9db772fb31c48e254bb56f4807cd6b' 
  AND token = 'gpLHQJsaBFjnhxZCzhfQoJeLeyJ7VR3ZALJ2y9q5koA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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