SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '103f8dc70d1afb8807e64167a570542b8256dd8432d59bf9ea13b1d28d0abccb' 
  AND token = '2E/NdZSQhfQBPoBeOgIHjsCeFXwzsVT4krw5fOXmZ4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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