SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f5c8c10fd3a74393cd6bee8a7a8e297f94451ce82fae7301427b0c66fb04733e' 
  AND token = 'Px8XrkfVS+wGWNALesnvNwsa4KhUcpCeK6cObdoptK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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