SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e80f18bb3d700d42988da09785f97415df698b38adcdee06c87d8c41403fb87f' 
  AND token = 'o8boQOaS0DcNV1MqHaEu3TA/8mxc5rlj0rYs/x8du30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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