SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bfdeae231a57bade1ae574b21a1296d0415a44c0b4caeda8ac0427dee36c1b20' 
  AND token = 'UoQnWUKzAYZOOKMg3UoreKuFyF3FHCkVeBXnScQ7+lY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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