SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3faa9b191189c46016c68930baaa050d8226fcfca22a15c0eac742bc81ca5c8e' 
  AND token = 'oiU7+9nrbg3WFIO8BJsFr+Kj3KshIFZMQASrgBsSvR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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