SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91584b68addeabbbf1c22e4863ae06a8e89b2905886fcbf28d893ec597c054cb' 
  AND token = '7CmyuXyLQdUerJIleoQZVWW4gvmaBf1NQBVwDfufvIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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