SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b870b215e2da33da80de01270dae39865e5c7af682e0595275767190c99f127' 
  AND token = '9I/wZtVHVfY9oCBxSLICvW74/ydTpeGWqzIAY40fM6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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