SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe13add68b00fcb98a8570b522644fe03dd6313c635c369df3f2224bcab36182' 
  AND token = 'jjtjYGIgWGmn6/9cdTPoXy4DQOK00cZAPcAenvol1vE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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