SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b840eeb53e09335af4e80b5c0e25da1e183caa9554504564ac530ad929ffc8' 
  AND token = 'HgxK8OAKnlFHXkP3vHhSlnHi06k5TSA8EwzikP/7vwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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