SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c37ac842e4c4bf3251b4fd9c2f0a36320c65ef734c45289976602eae40bd65a' 
  AND token = 'MYoxUGJj8KU3pNUGc8QszyN45wrOorVzZ2nS0Ve0RBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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