SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5184a45cfb2a4c0949b38eee39127f9c5e22288aa24783368c347c2c0d305749' 
  AND token = 'ygi9q3OY2buIrxUjuxQbZ/rUYeEAB+/4t1nS/ydSYXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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