SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c7c75f3cc249b2d05d0a12a4a8f5572421aa54bb920b53dca7da47ea932404' 
  AND token = 'JgCEBbM3/o+DLZI2VwYmfm7DuQ1B6gwM1KhPILQEAuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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