SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a4604120a09aba7c018ff1a8b05069dcafbcb1ab27e9a57d4803f698475fc57' 
  AND token = 'zqxxuBDTwoV/rsy80Eaw+sKXkcDqKLWTuh52cKtYjCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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