SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b54e9770ff40198b8239374b58fd5dc4fd2c61cc54c6d51123c833735b55991' 
  AND token = '3J4sgVaOZGlvcCORectt8wfZOAEaHFvoo2jXFfTVdjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}