SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '27ee2dad26500895d02c76da8be4cc4eab8fe456ca762b33231024e44984d1d5' 
  AND token = 'AjQZVWGw146m9Pzc32B+PDs3Ioj0VOaPXDhN5mDQY/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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