SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7530f0cc1cf82ea6701a54ea480404aca2469c32af36e4b663646392f2a1c51d' 
  AND token = 'zjNp40JhvY2l87i3FTSmPBXzu+vI+xNO9N1RpW7RCZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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