SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3b3d822bccf7410fa73ddad374bf579d1ba5edd6d0d2b99f79f367e5f52ddf85' 
  AND token = 'c2sGg0HPjuVwLMGo7r532N8wpBJhHeclvZUEEyS/Rdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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