SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e64947cc410c0f66bb41127746c784397a5ea75f312d30422b8b429499a6e41a' 
  AND token = 'rFJgTXwLTDE5qu6tyvE7NFGvZbPhtB2TFhZfYGthBpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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