SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '761f22baddc6f34532fe1c91d9ab596aa4e983cc69bae45febb7e931f5094713' 
  AND token = 'IMWxDPL4qxL1TonnoSxxYlUQSe9P4gebil0JtbgujgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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