SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8309aff73570e5a86c9acc9497166c280d0d8d1099a056de9b1ca4320d3e2a1' 
  AND token = '/jeRpnaNk7hc8In8BgrdwURiW2TyeOBeyiZ5Kxs5FUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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