SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef29619fec1038e42460133bf161ed040125d9acab8185f056178ab064aa5f41' 
  AND token = 'ODZkryTgvFsMclmX2mpyQqdX5r/Niyvj4nIhjFNF2jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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