SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a20cf200cb4d5c936e0b250a52c7074910171e2b3b193ac34fc21e59fa04d5e' 
  AND token = 'w3fYn4IWk+v/o1rJY9WhQedCFcaHunQtSaIf9L+qXpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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