SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be0a0606d982f79cc5a9cd28b66a8b87f1fcb2402f445312af19dff197d3861a' 
  AND token = 'QxLh/1KPRkEz+Ulgl6nrjobAFBDvM0jOYmrUk/BMsdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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