SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdd614c488d3aa5e02fc4199abded2c43acda5988b476365f5398ef26413e03a' 
  AND token = 'RkRY2hwPf9LfRoGbP7Xa6VFIJvyfKS9YpSPBWiXlGtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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