SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '379398e07fc4d45b4ad6d1fbcf5155df675da719126b4551c38141c0f8cd0703' 
  AND token = 'qFVZ1Zsn+MTz2TekmaoHdPCpjLT1QmjwkmH2OLKUjvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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