SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72a55f6f727d53993326a0a3d8b343d4087ed3b5afb43d453df0b62be7acd697' 
  AND token = 'E3p4WjU39BVLXhEmDWIzK+ZVM5Q/bWUGLwsMrufT+0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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