SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0b37df7974885c65575e8a5d727d3f6c7f9fbd9b3804702cbb0eb651e39b4dec' 
  AND token = 'QRsDqMLcaAnYoFViIndUOCDFoIbMahnauHfz9Rk/sog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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