SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef8f763880571ab8aa43ee69002e5cffb88ab53ce80ab3a53e7821479223be4' 
  AND token = 'N/9af0FDMZ9VM7eGTrdELO3fjaTuGAPUYQW6Up+q4K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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