SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'baa6b07cbcd004174eaeedc7e1af81424c8946c6b23d812cdb694b4049ca950a' 
  AND token = 'JqmMcIK8q+IAwmy1qz/+mTfpHKL3r9T6LsjqRm8Up3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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