SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70942e59e9f81f88384e3921ade1dfc15b519c6767f3ad71af08e141082e765d' 
  AND token = '9+PrKbeaizRUaUgMBckAbXv+3FooPVlx0YCQduOZ6Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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