SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d723bd4cd7b915f2c49d907bd890712e68858ac86aaee471634a09049fed6ea' 
  AND token = 'O3ghDgdjceIznNNnNTnPa/oWMXfIs8ofQEcamFJ2NaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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