SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b557dcbb012abe8220f009434de145f58e6eae9cec5aaa4e07b094efa7ed4d6b' 
  AND token = 'gCU2R553k0d2SZnr+eBdfUICgNzEahJVsP/TPiqh0uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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