SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12160fabcae58c283ed573e7908fdd9aa11b500483fdbda1ab60310a2c41e8a3' 
  AND token = '4mPl12mUuXn8aYhLgd9S99VytexIGAbn5GnenBjPLI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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