SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88ebed590e7e92b8ed6c18bc6c4eb2a863a72805d79e179f26dbf43b0187d4f7' 
  AND token = 'D/oOYalfFKGgj5sVHSJGhzGzCz8l0XyUM8WgeMQtXc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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