SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ef6932ceb6423b6308a2be6512d71ddf4a5552f33b8fb452c576dc31a1c2d456' 
  AND token = 'D2R94SiimS0qM6u4JWVHWAwyEwxuvADyudn5EjrwpTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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