SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a4b19c96b01741b080ad21f5cb762c9f51e5562710255af4a770c9efb68aecc' 
  AND token = 'ZR3+VqD17KMQsUTAC4vQ7EkcZwRGE015LjZRnmCbxbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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