SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8821c7890641a432daef835558e5f54b34928403c43183d1f59dbdd473bd7590' 
  AND token = '4iI6msN7cDyOkAJXewpzn+fLdj7HutKIp0xwmMpGJpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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