SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '570eb517d7771c176a14113bb3831a487239918459a1aca5aefacffb879bf9ed' 
  AND token = '4zp0swT91oBwrvmuXQpzUEk/Wk29xPVXB2dr5upBW+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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