SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8070e16a701827db6b3e787e836aa57290a3938aadc1121f84b85a7ddc9329fa' 
  AND token = 'qhiUuVPfgMB24osd1tjYa1lvHHII/tjk+gPkMvx6mWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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