SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfdcdbdaa43aca45425b10636e2b6c4f90e94ec49e58271402094be23660ef40' 
  AND token = 'U7SYxCEc4x0IfTVdzJUTkCCFClKIt2Dn5uj31czZeg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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