SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e98a13e3b332c4cca9a83291906a3dd656ff1a66286c7ae16b4dbb075987b56' 
  AND token = 'z14OWFtu9Z/D5xmoASyCqm4P/UI33WihgYjp51umB9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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