SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40435ddd78119b06d67f93509b0487b6348f84073e0137b316e931fd95b9e680' 
  AND token = 'd95ShdfjqL0dJvAMaagUl46C4CEf+yLryftrcVMpfEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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