SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daaff53740e2e5fc18bf7e9f8afaf56bcfbc778f3d951c83bd604da0c4c0b919' 
  AND token = 'gkB4sZP/F5QDNUXtnXRrPYBwMGmneA6WvDEFgsJmlb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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