SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '566e899708094305ffd44f353137fa6ec2fb45fcfe57f73d4fd12fc9e5284dd4' 
  AND token = 'REy0xR0hAnJwqZOUDymiNHf9P0v9zTGTtgTifYumqdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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