SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '571b717e3906ac4b501721d92dfa0a8a9e1acebd7df5d0452ff98a347d251875' 
  AND token = 'ZJFm1DhljY3mFqy8XQoAP6etImHnY5L01peGW6Dq4SI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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