SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3baf6a24d671c9f5c6f5af1f8317225728a670ef1747c498e5343f9d534d5b30' 
  AND token = 'e+bLCxy7MKzU/tfG7pFubqQg7BM8BJP0DGsrWBxlErg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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