SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c1bb0db8a9999a6bb8460201c0db9bd1f190dbb743a70b6b275bbf3b504cd3' 
  AND token = 'fTF+BsOOg3vPl8jwPCmqd2M8qmq+0pAzmznwIB0zYO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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