SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cdc7fce8a708b334a8052b493f0085615a44dd5c268a4d28a9a4afe709913ac' 
  AND token = 'jA88jAKZKPWNjmyb44ZNGr0xiyCKjLOgXG8afDynuek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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