SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ae73cd596031de21f58a12b5e980c2dd352030afe89ebd8046420099c78e53fe' 
  AND token = 'l8J5sP8anBG9ae2VYTFNsOvh7IQEiFEd+3IUlbA0mHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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