SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b3444291eb4ed34470d557293b12ccbe7ce4268327a3e96934992be8124f380' 
  AND token = 'pqCsFm1OCZrIl6dG9DZnjipQJ4rMkkvQpo+EOjsV5eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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