SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffde558bba2df43e511e133e142d106815939ccf6fed54bb243d6574649a1753' 
  AND token = 'LJGL8hTnZboduD5VoXyuebMJI4oR4q8OF6bE6N9xaJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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