SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a1b30c327d14f4ae874c5989db0de6bd86e6b75690609ffc0f3a9c22938f8254' 
  AND token = 'HDkZytpShtYbL6cZQDG9SJiEF0UZUkuHXXJFT3v47fA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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