SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '02e73be1f5253971af85fe5f84ba259042e8e2c6598b0d477e28bfc5ddc14e09' 
  AND token = 'buznyFMsrZkFn4BrZ1rq8kD0TGRFsAuTijBRXS6M3tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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