SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e51f66d0705997763c110c16fa79580467fef276a4c16da404ce7ae494ed17e' 
  AND token = 'OsbOYJPOjQsIPUFi/jcOmh0W2Lrlw8zAuvDz8YMQrlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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