SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4273fb052321157e1e47505e65647103149eaf01b6ef25a944c07b2831f2156' 
  AND token = 'Wp3PM+4S8m1/jPYAYn/cszGy/ZRvh2e2ALNWBluBp1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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