SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef0f0828c93edf3ad886e3dadd2915a44ff0bfbf066cae1afaed797974209ce3' 
  AND token = 'FoyhJw9dTqvOqZhsPcFOyjQ1/O60fruYKKxwGh0nl4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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