SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'bdf53d163deaed104bb25010d8e94aa0a836bcc5f65107c00d7f3d379ccc3250' 
  AND token = 't0p6PklTlfLxzgPdP1RdfO955Gs8W8jQu7Bk8GE/YWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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