SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae692ddd339adb469ea27a3383ebafd795025eb355ec915d1f6cb6cb297f4bd9' 
  AND token = 'njbUoIyxFY6Oy05BWyfcL3k8Nk5T9yMIDz0EBJ9T1HU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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