SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3d2b5a50381378dc5914d7af2a03ca851499e8e56d30461b63b21dbd0cdc1674' 
  AND token = '15MV+fyjyLvsGzPYJaSluMUpvgSC62cM00LoVfMdf8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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