SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7591af4637df11dff7483bf9a409031a3bc699e01f804e372761352dc138296f' 
  AND token = 'Ec1WLNbnrhhnUWeUA0SNH7ddkpztjE/g6Kr5NOXSf+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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