SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38e29e22fd3ba648f9d18fb246dde1065099e3f7ab26e31ce99b897667aad510' 
  AND token = '0OgtmNBOzIEakaKq8LZdeSc546POPoGMkpKbvWaQAPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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