SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551cddd4844c079bb581475dad24a69406eeead8343fa929e39feee9b42db6da' 
  AND token = 'bq7DYHKynB6RuzQoyeB2LtDwZk7AyZlYmwO9lXITu8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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