SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59865e896813ef1793f70d177531b74d05d8bb02124bef2800241cf6fe14523' 
  AND token = 'o+srvIYeO02BrgYHMeTbbFsnKlt5zgWv+SjPDqAmL00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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