SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ee20ec4698a020a41c6869e85902649f68fd669bfaf37dd3af6a726e8cac169' 
  AND token = 'wcdJ8SE6id0PQ6PqUpjAOR5WWdsQ5+L2t8gi2sYi+oA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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