SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '571606883ce8db6d68decf70e63009965095cacfa27084709c1b539a0c621efb' 
  AND token = 'C0YD+Uz/MQELPYvV11ksra2Gm+vIWpZU5DT8zO9hw/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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