SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0adeb67604be6c8ab7fa8fde6037acf4fe61a3c9c45a337eeb091494e727543' 
  AND token = '1jfW59Nv+otGdvvr0yG+AInfpHsAxi2KggrfVzycBkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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