SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4caf9a759127dd2fa9c8d897e2ccf82447c4288b870f8292ed346fdb97acadf9' 
  AND token = 'hb3qfT60gAh0MbaFKiPEFQ2sjMyenaQol+WZBfBQtB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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