SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59a596ef2209a50115b9c135f9715363a3660086f47f145b8f4bef20bcbb6e51' 
  AND token = 'DejWpi6aGeVjg8lVF7KWN1sCzBOU75y2seQBsHnJz7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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