SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b810c35c5ced987d959d91dbdf6f92b7c5f64ed4f765acdf8443a590dfe31686' 
  AND token = 'XuqIm4M3WQEErwt4Q7J25lu9RlEYBEmRIY4r/s6jV7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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