SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beeb3070bf5a3aa0b41adb3ef5d904d15c53866fa6afbe2312173db92c31b745' 
  AND token = 'w2FKuyHRjdauIhSW/Qa1ppk8nyA/ZjVKkcBhyjY+hBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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