SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e938c1838d0fad96f133551e3d575ec15b2daf1dc8886deee000a7977e9f40e' 
  AND token = 'YSSNwZiZfmJjaFX4dGBaJndJfMLdl4kFJ+i6VUjTYVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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