SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e2ada6fe45d62a066793fe312f58dc3c0cc7786c8c9711a52c8f6ec572135fa0' 
  AND token = '7BXx2Q3uTlOSsjRxuIlc43m91u1WGip/dlO/wX1czBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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