SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '000471d5b929f84d20556b4dc0c7181f3efd3a44491f358b496f2e8f96625aa9' 
  AND token = '2VGACqB4TR3+wBeTftkYddu9MriTFPU2VCAG7Hugq6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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