SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '143e3633a21c9dc423b859b9b9d05d028acbc70828040997fc64b5af89156a91' 
  AND token = '0o2LsJWoiVxujmN+HA9inZXMGWASGHwt80dzrKz9iWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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