SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328715b5fb40855ec0963a0bfca4818a075eb7f5d5305b5ce0de1dce752d4c11' 
  AND token = 'bo/2OUe1KpMgcd6YzSIogxDxFZlg1A2Xmt2kjNn2ezE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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