SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6cfc5c1d43a9c3a7e11602e844fd48affd371c0504aede79879c9e05471d9bc' 
  AND token = 'x2xXzqflXkLyAqImhljNMcG10riqOi3lGiaduI69k3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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