SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4ca4b519de77b47c16eab3ab38de5f2292a1475ca211ae975f7679ddad100b9' 
  AND token = 'U6/f/uQbm1PTJ9TRtaBbas27ClTQqkha8JFTJrCOMns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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