SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd75f499cdcc26f1327e4cefa1ec12bb312ed61ba74fecd91bb02024160e2b029' 
  AND token = 'P/sRS2jlKWBEZhyxtPQ7Y/Xrzq7qlc3wZSRHzRfrvRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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