SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e8fbd309c497dd59654c50885ffde3a7141ad8c370979dbfd40ad66c6ad3da0' 
  AND token = '/kBOdJH62W7SbC0zUdUYT1rzQbXmG0RAXZRjgboKijA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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