SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab95e377851df446743d36a2389d846412a777bd3bf333994087f74568050bec' 
  AND token = 'yzc1guIEi25//vUtc+w3XDUi2Mu3tvR9Et80Y6Qj/dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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