SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53a099cff22a87e14b943038e944731099294f7e30c358ca113c1b572ea3f2e4' 
  AND token = 'JRSnyTqFwmSY0BKa07936J5qSXkkOuGNoreq9yGQnjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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