SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2c065e5dc2f69df9d4cd7aa819f49e40358e0cb0e8437037251b81b46383584' 
  AND token = 'scMA/X1+YbqLou1TKuz8IzYJlHCzVHvSxGEUTmgcLqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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