SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88314a536d7c16c455ddf253ea411878c97aedf8896b79eaaf364b91b7c349e2' 
  AND token = 'ULOLOpsoLtHDQywSBomubsCc3so1RL6zJxBFvXYuT58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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