SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13dc7fe769d20f525417115879a465778a4b14b7b3738dbf29b742d9d2a5ead4' 
  AND token = '7+9v0fKo8wKnhrcZxpZ6lDWvEizYlvhhwRxACyuS0ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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