SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecc9fda4b597d4f20970cf15157543c8727d3214850a8dd6f185b274c011d16' 
  AND token = '34CBgQhmR/hX/pKhv8eLP1RfFuQo5KmLtuFThormx2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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