SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7976d7487a5b86c0a578abd0ee53666880655e0132c49a87958189ac398981ec' 
  AND token = 'hZCj6oHGkbRmZzZrfTye7OYZS6LDGTNx3smRRmxfXY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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