SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26039a8bef5deef4cac986794a7d8e4d61e17b38deb04d4aaf9045122008fd03' 
  AND token = 'Y+TM3KKZgIGhnIZAmkmzKyIvjYNzwN0lnGTDTFzhNsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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