SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14bc81ad7fe8265f55e417752d91e6107e528e03e2ad14b6a281e8ecd5536bd4' 
  AND token = 'et48IccvwK28l+ZAAddNyIfcPOrrY2j75n0gtzT70tU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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