SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3fd24b839dc68f8e2b07691f7a79886df225ffc982fcac9e83e84902bbb4b79a' 
  AND token = 'L5DWv6RIHgVbbv1mjAwVsNfIH33+/eLHdpiyGiBVYPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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