SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '55d448329302bfe569afc346d48b7b67cb6695b5c6383b9284c138b261517abc' 
  AND token = 'N2JOG7ImVajf3EiCcDlkY146k0J01k/IF8g2jJbaG/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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