SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ff4715747e97655240ccb2e1de9ae1696744baad8e457d8535e3410c1082d8' 
  AND token = 'IKRYroq1BEaGIfujPkL49bz9VaCeGRnRIqkGeLrmtRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00142

JSON explain

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