SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c043a9d76fe212ad0c78e33b05423da6b53e570888d2271eda5f43085a2107e2' 
  AND token = 'aF4jxJyl9GfuGYZjFBFSnvwgpxkak6zikghtfN0Xgjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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