SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '64785d1f330906dc96d553311beba848edd32a61cf4240d8de0b6666b990375f' 
  AND token = 'Ou++TzAMEQrlmtRRYeQFgDG11CTU4wIkwyPXs0JE8s4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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