SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '455ea80789bec96eaf0d3cf3b1f22c26c8a324e2433bab746fb00239e0a70d2f' 
  AND token = '2vEFG27sSASiTtoAsJ0+r3XNRJX+sL80ZfFkQ6Dkam8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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