SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a257fa41c991582a31511c9a0810d655ef0d2f9afd09564363d8388bbcc959b6' 
  AND token = 'aGH1oD6Dl3ipi3KoKo3vWc485pxrQd2qxFWOptQeXlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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