SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2ad514fadf5afc3882a01bae10a9f330b20bda80a0280b586d21ff84a20784b' 
  AND token = 'CtbBFPmWTGW9dNpWN1wsHITT+eifgnG8QuqbcqmZKe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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