SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1120a3162d3402218ebd980673a35da9f96f2965fef4798c6c5dba0e8efeafd' 
  AND token = 'Ggov5dAcBB47IB7PM84s+wpDwosulQjRtY8RBjGM0+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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