SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7135475f214b300a6bcd653f628f48cc96a3d07834af1c410b8c4aa604463332' 
  AND token = 'yOxKjphTj195pkPPB1vV8wQsJNwd0ROaz2w+/dLHzmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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