SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f52a5748db56a80392f3d6afc0c15e21c1af24e2ffc282cbdb5ead156fcf2cf8' 
  AND token = 'wIOlcTKyeXbCjXYcE81rJoQ0+7N5qvGzV1b/V1BPgJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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