SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2677dd7f0f1ed4ae5dd80571797f308e5c098e4360b12da641b89b716a799eb5' 
  AND token = 'GDl2cVTQOSpQRrYnAaz8hk+MLoZG8RIQVIQ6whUj+6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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