SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2cf001b4f920d41d79a47653afbf089594ab2b3cb4c4840a82d70bcf1fad66' 
  AND token = '5GNVaJaTXWemhWg+JpgHCj+9LDMC2pVpP3bIGz0Thb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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