SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '753b40649d59c6f0ba56db82dab7b23212ffc2bfae8a48a066be56d361ce3703' 
  AND token = 'aNKauCiac9C715W+YMy/z7fNn0kt0UajrT0lr0kqR10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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